A break in the core of a fiber optic cable often causes failure of the optical link between two optical transceivers or associated optical network devices. To help diagnose the cause of this type of mechanical failure and to test a new or repaired fiber optical cable, tools have been developed to inspect for such a break. One such tool is a Visual Fault Locator (VFL). VFLs operate by connecting a fiber optic connector (sometimes referred to in the military and aerospace industries as a terminus) of a fiber optical cable to be inspected to a compatible port of the VFL. The port of the VFL typically is not a receptacle that coordinates with the connector. Rather, to accommodate multiple connector types and/or ferrule sizes (e.g., 1.25 mm ferrules and 2.5 mm ferrules), the port merely engages the ferrule at the terminal end of the cable under test. Therefore, the connector of the cable under test is only loosely secured to the port and the connector may easily become detached from the port if not held in place.
The VFL illuminates the core of the fiber optical cable with laser light in the visual spectrum. Typically, red laser light is used. When the light is incident on a break in the core of the fiber optical cable, the light will “leak” from the break and, depending on the jacket arrangement, will be visible at the break in the core through the cladding and jacket of the fiber optical cable. During illumination, a person may visually inspect the cable for breaks by looking for leaking light. This technique is most applicable for testing fiber optical cables with relatively short lengths, such as lengths of 200 meters or less.
Currently available VFLs are hand-held tools that include all functional components of the VFL in a housing, such as electronics, a power source (e.g., batteries), and the emitting laser. The port for the connector of the fiber optic cable is mounted to the housing. A button board that retains user control buttons is also mounted to the housing. Some VFLs may be operated to continuously emit laser light and/or to pulse the laser light. Most VFLs may be used to test multimode fibers and single mode fibers. VFL functionality also may be found in more advanced test equipment, such as an optical power meter or an optical time-domain reflectometer (OTDR).
The conventional VFL form-factor is portable, but is often inconvenient to use to test cables that have been connected to rack-mounted optical network devices (e.g. network data switches). An exemplary commercially available VFL while in use in a data center is shown in FIG. 1. As can be seen, one problem with conventional VFLs is that the VFL must be physically supported in a tight space and the operator may need to hold the connector into the port of the VFL. This can be a difficult task if the operator is not assisted by another person and needs to leave the location of the VFL to inspect the cable being tested or engage in other activities involving the user's hands.